Unlimited undo/redo support. Most edit operations on the Bayesian network
are undoable. A notable exception is learning of network and CPTs.

Cut/copy/paste support. When a set of nodes is selected these can be placed on
a clipboard (internal, so no interaction with other applications yet) and
a paste action will add the nodes. Nodes are renamed by adding "Copy of" before
the name and adding numbers if necessary to ensure uniqueness of name.
Only the arrows to parents are copied, not these of the children.

The Add Node menu brings up a dialog (see below) that allows to specify the name of the
new node and the cardinality of the new node. Node values are assigned the
names 'Value1', 'Value2' etc. These values can be renamed (right click the node
in the graph panel and select Rename Value). Another option is to copy/paste
a node with values that are already properly named and rename the node.

The Add Arc menu brings up a dialog to choose a child node first;

Then a dialog is shown to select a parent. Descendants of the child
node, parents of the child node and the node itself are not listed since
these cannot be selected as child node since they would introduce cycles
or already have an arc in the network.

The Delete Arc menu brings up a dialog with a list of all arcs that
can be deleted.

The list of eight items at the bottom are active only when a group of at least
two nodes are selected.
Align Left/Right/Top/Bottom moves the nodes in the selection such
that all nodes align to the utmost left, right, top or bottom node in the
selection respectively.
Center Horizontal/Vertical moves nodes in the selection halfway
between left and right most (or top and bottom most respectively).
Space Horizontal/Vertical spaces out nodes in the selection evenly
between left and right most (or top and bottom most respectively). The order
in which the nodes are selected impacts the place the node is moved to.